LTC3225 150mA Supercapacitor Charger FEATURES DESCRIPTION n The LTC®3225 is a programmable supercapacitor charger designed to charge two supercapacitors in series to a fixed output voltage (4.8V/5.3V selectable) from a 2.8V/3V to 5.5V input supply. Automatic cell balancing prevents overvoltage damage to either supercapacitor. No balancing resistors are required. n n n n n n n n Low Noise Constant Frequency Charging of Two Series Supercapacitors Automatic Cell Balancing Prevents Capacitor Overvoltage During Charging Programmable Charging Current (Up to 150mA) Selectable 2.4V or 2.65V Regulation per Cell Automatic Recharge IVIN = 20μA in Standby Mode ICOUT < 1μA When Input Supply is Removed No Inductors Tiny Application Circuit (3mm × 2mm DFN Package, All Components <1mm High) APPLICATIONS n n Current Limited Applications with High Peak Power Loads (LED Flash, PCMCIA Tx Bursts, HDD Bursts, GPRS/GSM Transmitter) Backup Supplies Low input noise, low quiescent current and low external parts count (one flying capacitor, one bypass capacitor at VIN and one programming resistor) make the LTC3225 ideally suited for small battery-powered applications. Charging current level is programmed with an external resistor. When the input supply is removed, the LTC3225 automatically enters a low current state, drawing less than 1μA from the supercapacitors. The LTC3225 is available in a 10-lead 3mm × 2mm DFN package. L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION Charging Profile with 30% Mismatch in Output Capacitance, CTOP < CBOT VIN 2.8V/3V TO 5.5V VIN COUT 0.6F 2.2μF VOUT 4.8V/5.3V C+ 1μF ON/OFF OUTPUT PROGRAMMING CX LTC3225 C– GND SHDN PGOOD SHDN 5V/DIV IVIN 300mA/DIV 0.6F 100k VCOUT 2V/DIV VSEL PROG 12k 3225 TA01a VTOP-VBOT 200mV/DIV 5s/DIV VSEL = VIN RPROG = 12k CTOP = 1.1F CBOT = 1.43F CTOP INITIAL VOLTAGE = 0V CBOT INITIAL VOLTAGE = 0V 3225 TA01b 3225f 1 LTC3225 ABSOLUTE MAXIMUM RATINGS (Note 1) PIN CONFIGURATION VIN, COUT to GND ......................................... –0.3V to 6V SHDN, VSEL ...................................... –0.3V to VIN + 0.3V COUT Short-Circuit Duration ............................. Indefinite IVIN Continuous (Note 2) ......................................350mA IOUT Continuous (Note 2) .....................................175mA Operating Temperature Range (Note 3).... –40°C to 85°C Storage Temperature Range................... –65°C to 125°C TOP VIEW C+ 1 10 COUT C– 2 9 VIN 8 GND SHDN 4 7 PROG PGOOD 5 6 VSEL CX 3 11 DDB PACKAGE 10-LEAD (3mm s 2mm) PLASTIC DFN TJMAX = 125°C, θJA = 76°C/W EXPOSED PAD (PIN 11) MUST BE SOLDERED TO LOW IMPEDANCE GND PLANE (PIN 8) ON PCB ORDER INFORMATION Lead Free Finish TAPE AND REEL (MINI) TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3225EDDB#TRMPBF LTC3225EDDB#TRPBF LCYR 10-Lead (3mm × 2mm) Plastic DFN TRM = 500 pieces. Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ –40°C to 85°C ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 3.6V, CIN = 2.2μF, CFLY = 1μF, unless otherwise specified. SYMBOL PARAMETER CONDITIONS VIN-UVLO Input Supply Undervoltage Lockout High-to-Low Threshold VSEL = VIN VSEL = 0 VIN-UVLO-HYS Input Supply Undervoltage Lockout Hysteresis VSEL = VIN VSEL = 0 VIN Input Voltage Range VSEL = VIN VSEL = 0V l l 3 2.8 VCOUT Charge Termination Voltage Sleep Mode Threshold (Rising Edge) VSEL = VIN VSEL = 0V l l 5.2 4.7 l l MIN TYP MAX UNITS 2.65 2.4 2.75 2.5 2.85 2.6 V V 150 140 5.3 4.8 mV mV 5.5 5.5 V V 5.4 4.9 V V VCOUT-HYS Output Comparator Hysteresis VTOP/BOT Maximum Voltage Across Each of the Supercapacitors After Charging VSEL = VIN VSEL = 0V l l 100 mV IQ-VIN No Load Operating Current at VIN IOUT = 0mA l 20 40 μA ISHDN-VIN Shutdown Current SHDN = 0V, VOUT = 0V l 0.1 1 μA ICOUT COUT Leakage Current VOUT = 5.6V, SHDN = 0V VOUT = 5.6V, Charge Pump in Sleep Mode VOUT = 5.6V, SHDN Connected to VIN with Input Supply Removed l l 1 2 3 4 1 μA μA μA IVIN Input Charging Current VIN = 3.6V, RPROG = 12k, CTOP = CBOT 306 mA VIN = 3.6V, RPROG = 60k, CTOP = CBOT 55 mA 2.75 2.5 V V 3225f 2 LTC3225 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 3.6V, CIN = 2.2μF, CFLY = 1μF, unless otherwise specified. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS IOUT Output Charging Current VIN = 3.6V, RPROG = 12k, VOUT = 4.5V, CTOP = CBOT 125 150 175 mA VIN = 3.6V, RPROG = 60k, VOUT = 4.5V, CTOP = CBOT 26 mA VPGOOD PGOOD Low Output Voltage IPGOOD = –1.6mA l 0.4 V IPGOOD-LEAK PGOOD High Impedance Leakage Current VPGOOD = 5V l 10 μA VPG PGOOD Low-to-High Threshold Relative to Output Voltage Threshold l 92 94 96 % l 0.25 1.2 2.5 % VPG-HYS PGOOD Threshold Hysteresis Relative to Output Voltage Threshold ROL Effective Open-Loop Output Impedance (Note 4) VIN = 3.6V, VOUT = 4.5V fOSC CLK Frequency l 0.6 VIH Input High Voltage l 1.3 VIL Input Low Voltage l IIH Input High Current l IIL Input Low Current l Ω 8 0.9 1.5 MHz VSEL, SHDN Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliabilty and lifetime. Note 2: Based on long-term current density limitations. V 0.4 V –1 1 μA –1 1 μA Note 3: The LTC3225 is guaranteed to meet performance specifications from 0°C to 85°C. Specifications over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. Note 4: Output not in regulation; ROL ≡ (2 • VIN – VOUT)/IOUT TYPICAL PERFORMANCE CHARACTERISTICS (TA = 25°C, CFLY = 1μF, CIN = 2.2μF, CTOP = CBOT , unless otherwise specified) IOUT vs RPROG IOUT vs VOUT (RPROG = 12k) 160 VIN = 3.6V VOUT = 4.5V 140 100 160 90 80 140 120 80 60 EFFICIENCY (%) 100 100 80 60 40 0 0 10 20 30 40 RPROG (kΩ) 50 60 70 3225 G01 0 0 0.5 1 1.5 2 2.5 3 VOUT (V) 3.5 4 4.5 60 50 40 20 VIN = 2.8V VIN = 3.6V VIN = 5.5V 20 VSEL = 0 30 CTOP = CBOT 40 20 VSEL = VIN 70 120 IOUT (mA) IOUT (mA) Efficiency vs VIN 180 10 0 5 3225 G02 ILOAD = 100mA CTOP = CBOT 2.5 3 3.5 4 VIN (V) 4.5 5 5.5 3525 G03 3225f 3 LTC3225 TYPICAL PERFORMANCE CHARACTERISTICS (TA = 25°C, CFLY = 1μF, CIN = 2.2μF, CTOP = CBOT , unless otherwise specified) 30 VIN = 3.6V VOUT = 4.5V 6 9 5 EXTRA IIN (mA) 10 IIN (μA) 4 3 25 TA = 85°C 8 20 TA = 25°C 7 TA = –40°C 6 ROL (Ω) 7 Charge Pump Open-Loop Output Resistance vs Temperature (2VIN – VCOUT)/IOUT No-Load Input Current vs Supply Voltage Extra Input Current vs Output Current (IVIN – 2 • IOUT) 15 10 2 1 5 0 0 VIN = 3.6V VOUT = 4.5V 5 4 3 2 1 0 20 60 80 100 120 140 160 IOUT (mA) 40 2.5 3 3.5 4 VIN (V) 4.5 5 5.5 Oscillator Frequency vs Supply Voltage FREQUENCY (MHz) 85 SHDN 5V/DIV VIN 20mV/DIV IVIN 300mA/DIV IVIN 200mA/DIV VCOUT 2V/DIV 0mA TA = –40°C 0.91 TA = 85°C RPROG = 12k 0.90 60 3225 G08 Input Ripple and Input Current TA = 25°C 35 10 TEMPERATURE (°C) Charging Profile with Unequal Initial Output Capacitor Voltage (Initial VTOP = 1.3V, VBOT = 1V) 0.94 0.93 –15 3225 G05 3225 G04 0.92 0 –40 200ns/DIV 3225 G06 VTOP-VBOT 500mV/DIV 2s/DIV VSEL = VIN RPROG = 12k CTOP = CBOT = 1.1F 0.89 3225 G09 0.88 2.5 3 3.5 4 VIN (V) 4.5 5 5.5 3225 G07 Charging Profile with Unequal Initial Output Capacitor Voltage (Initial VTOP = 1V, VBOT = 1.3V) Charging Profile with 30% Mismatch in Output Capacitance (CTOP > CBOT) Charging Profile with 30% Mismatch in Output Capacitance (CTOP < CBOT) SHDN 5V/DIV SHDN 5V/DIV SHDN 5V/DIV IVIN 300mA/DIV IVIN 300mA/DIV IVIN 300mA/DIV VCOUT 2V/DIV VCOUT 2V/DIV VCOUT 2V/DIV VTOP-VBOT 200mV/DIV VTOP-VBOT 200mV/DIV VTOP-VBOT 500mV/DIV 2s/DIV VSEL = VIN RPROG = 12k CTOP = CBOT = 1.1F 3225 G10 5s/DIV VSEL = VIN RPROG = 12k CTOP = 1.43F CBOT = 1.1F CTOP INITIAL VOLTAGE = 0V CBOT INITIAL VOLTAGE = 0V 3225 G11 5s/DIV VSEL = VIN RPROG = 12k CTOP = 1.1F CBOT = 1.43F CTOP INITIAL VOLTAGE = 0V CBOT INITIAL VOLTAGE = 0V 3225 G12 3225f 4 LTC3225 PIN FUNCTIONS C+ (Pin 1): Flying Capacitor Positive Terminal. A 1μF X5R or X7R ceramic capacitor should be connected from C+ to C–. VSEL (Pin 6): Output Voltage Selection Input. A logic low at VSEL sets the regulated COUT to 4.8V; a logic high sets the regulated COUT to 5.3V. Do not float the VSEL pin. C– (Pin 2): Flying Capacitor Negative Terminal. PROG (Pin 7): Charging Current Programming Pin. A resistor connected between this pin and GND sets the charging current. (See Applications Information section). CX (Pin 3): Midpoint of Two Series Supercapacitors. This pin voltage is monitored and forced to track COUT (CX = COUT/2) during charging to achieve voltage balancing of the top and bottom supercapacitors. GND (Pin 8): Charge Pump Ground. This pin should be connected directly to a low impedance ground plane. SHDN (Pin 4): Active Low Shutdown Input. A low on SHDN puts the LTC3225 in low current shutdown mode. Do not float the SHDN pin. VIN (Pin 9): Power Supply for the LTC3225. VIN should be bypassed to GND with a low ESR ceramic capacitor of more than 2.2μF. PGOOD (Pin 5): Open-Drain Output Status Indicator. Upon start-up, this open-drain pin remains low until the output voltage, VOUT, is within 6% (typical) of its final value. Once VOUT is valid, PGOOD becomes Hi-Z. If VOUT falls 7.2% (typical) below its correct regulation level, PGOOD is pulled low. PGOOD may be pulled up through an external resistor to an appropriate reference level. This pin is Hi-Z in shutdown mode. COUT (Pin 10): Charge Pump Output Pin. Connect COUT to the top plate of the top supercapacitor. COUT provides charge current to the supercapacitors and regulates the final voltage to 4.8V/5.3V. Exposed Pad (Pin 11): This pad must be soldered to a low impedance ground plane for optimum thermal performance. 3225f 5 LTC3225 SIMPLIFIED BLOCK DIAGRAM CFLY 9 1 2 C+ VIN 4 C– VIN SHDN SOFT-START AND SHUTDOWN CONTROL UVLO THERMAL PROTECTION 3000i POR 1.2V COUT CX CHARGE PUMP RUN CTOP 3 CBOT GND 8 i 7 10 PROG CLK RPROG RUN/STOP R1 OSCILLATOR – C1 R2 + VREF – 2% 1.2V POR PGOOD VREF + 1.088V 6 VSEL VREF – 6% VREF – 7.2% 5 C2 – 3225 F01 Figure 1 3225f 6 LTC3225 OPERATION The LTC3225 is a dual cell supercapacitor charger. Its unique topology maintains a constant output voltage with programmable charging current. Its ability to maintain equal voltages on both cells while charging protects the supercapacitors from damage that is possible with other charging methods, without the use of external balancing resistors. The LTC3225 includes an internal switched capacitor charge pump to boost VIN to a regulated output voltage. A unique architecture maintains relatively constant input current for the lowest possible input noise. The basic charger circuit requires only three external components. ICOUT = 1 •I 2 VIN If the leakage currents or capacitances of the two supercapacitors are mismatched enough that varying the charging current is not sufficient to balance their voltages, the LTC3225 stops charging the capacitor with the higher voltage until they are again balanced. This feature protects either capacitor from experiencing an overvoltage condition. Shutdown Mode Normal Charge Cycle Operation begins when the SHDN pin is pulled above 1.3V. The COUT pin voltage is sensed and compared with a preset voltage threshold using an internal resistor divider and a comparator. The preset voltage threshold is 4.8V/5.3V selectable with the VSEL pin. If the voltage at the COUT pin is lower than the preset voltage threshold, the oscillator is enabled. The oscillator operates at a typical frequency of 0.9MHz. When the oscillator is enabled, the charge pump operates charging up COUT. The input current drawn by the internal charge pump ramps up at approximately 20mA/μs each time the charge pump starts up from shutdown. Once the output voltage is charged to the preset voltage threshold, the part shuts down the internal charge pump and enters into a low current state. In this state, the LTC3225 consumes only about 20μA from the input supply. The current drawn from COUT is approximately 2μA. Asserting SHDN low causes the LTC3225 to enter shutdown mode. When the charge pump is first disabled, the LTC3225 draws approximately 1μA of supply current from VIN and COUT. After VOUT is discharged to 0V, the current from VIN drops to less than 1μA. With SHDN connected to VIN, the output sinks less than 1μA when the input supply is removed. Since the SHDN pin is a high impedance CMOS input, it should never be allowed to float. Output Status Indicator (PGOOD) During shutdown, the PGOOD pin is high impedance. When the charge cycle starts, an internal N-channel MOSFET pulls the PGOOD pin to ground. When the output voltage, VOUT, is within 6% (typical) of its final value, the PGOOD pin becomes high impedance, but charge current continues to flow until VOUT crosses the charge termination voltage. When VOUT drops 7% below the charge termination voltage, the PGOOD pin again pulls low. Automatic Cell Balancing The LTC3225 constantly monitors the voltage across both supercapacitors while charging. When the voltage across the supercapacitors is equal, both capacitors are charged with equal currents. If the voltage across one supercapacitor is lower than the other, the lower supercapacitor’s charge current is increased and the higher supercapacitor’s charge current is decreased. The greater the difference between the supercapacitor voltages, the greater the difference in charge current per capacitor. The charge currents can increase or decrease as much as 50% to balance the voltage across the supercapacitors. When the cell voltages are balanced, the supercapacitors are charged at a rate of approximately: Current Limit/Thermal Protection The LTC3225 has built-in current limit as well as overtemperature protection. If the PROG pin is shorted to ground, a protection circuit automatically shuts off the internal charge pump. At higher temperatures, or if the input voltage is high enough to cause excessive self-heating of the part, the thermal shutdown circuitry shuts down the charge pump once the junction temperature exceeds approximately 150°C. It will enable the charge pump once the junction temperature drops back to approximately 135°C. The LTC3225 is able to cycle in and out of thermal shutdown indefinitely without latch-up or damage until the overcurrent condition is removed. 3225f 7 LTC3225 APPLICATIONS INFORMATION Programming Charge Current The charging current is programmed with a single resistor connecting the PROG pin to ground. The program resistor and the input/output charge currents are calculated using the following equations: IVIN = 3600 V RPROG IOUT = IVIN (with matched outp put capacitors) 2 An RPROG resistor value of 2k or less (i.e., short circuit) causes the LTC3225 to enter overcurrent shutdown mode. This mode prevents damage to the part by shutting down the internal charge pump. Power Efficiency The power efficiency (η) of the LTC3225 is similar to that of a linear regulator with an effective input voltage of twice the actual input voltage. In an ideal regulating voltage doubler the power efficiency is given by: η2xIDEAL = POUT VOUT • IOUT VOUT = = PIN VIN • 2IOUT 2VIN At moderate to high output power the switching losses and quiescent current of the LTC3225 are negligible and the above expression is valid. For example, with VIN = 3.6V, IOUT = 100mA and VOUT regulated to 5.3V, the measured efficiency is 71.2% which is in close agreement with the theoretical 73.6% calculation. Effective Open-Loop Output Resistance (ROL) The effective open-loop output resistance (ROL) of a charge pump is an important parameter that describes the strength of the charge pump. The value of this parameter depends on many factors including the oscillator frequency (fOSC), value of the flying capacitor (CFLY), the non-overlap time, the internal switch resistances (RS) and the ESR of the external capacitors. Output Voltage Programming The LTC3225 has a VSEL input pin that allows the user to set the output threshold voltage to either 4.8V or 5.3V by forcing a low or high at the VSEL pin respectively. Charging Time Estimation The estimated charging time when the initial voltage across the two output supercapacitors is equal is given by the equation: t CHRG = ( COUT • VCOUT – VINI ) IOUT where COUT is the series output capacitance, VCOUT is the voltage threshold set by the VSEL pin, VINI is the initial voltage at the COUT pin and IOUT is the output charging current given by: IOUT = 1800 V RPROG When the charging process starts with unequal initial voltages across the output supercapacitors, only the capacitor with the lower voltage level is charged; the other capacitor is not charged until the voltages equalize. This extends the charging time slightly. Under the worst-case condition, whereby one capacitor is fully depleted while the other remains fully charged due to significant leakage current mismatch, the charging time is about 1.5 times longer than normal. Thermal Management For higher input voltages and maximum output current, there can be substantial power dissipation in the LTC3225. If the junction temperature increases above approximately 3225f 8 LTC3225 APPLICATIONS INFORMATION 150°C, the thermal shutdown circuitry automatically deactivates the output. To reduce the maximum junction temperature, a good thermal connection to the PC board is recommended. Connecting the GND pin (Pin 8) and the Exposed Pad (Pin 11) of the DFN package to a ground plane under the device on two layers of the PC board can reduce the thermal resistance of the package and PC board considerably. VIN Capacitor Selection The type and value of CIN controls the amount of ripple present at the input pin (VIN). To reduce noise and ripple, it is recommended that low equivalent series resistance (ESR) multilayer ceramic chip capacitors (MLCCs) be used for CIN. Tantalum and aluminum capacitors are not recommended because of their high ESR. The input current to the LTC3225 is relatively constant during both the input charging phase and the output charging phase but drops to zero during the clock non-overlap times. Since the non-overlap time is small (~40ns) these missing “notches” result in only a small perturbation on the input power supply line. Note that a higher ESR capacitor, such as a tantalum, results in higher input noise. Therefore, ceramic capacitors are recommended for their exceptional ESR performance. Further input noise reduction can be achieved by powering the LTC3225 through a very small series inductor as shown in Figure 2. A 10nH inductor will reject the fast current notches, thereby presenting a nearly constant current load to the input power supply. For economy, the 10nH inductor can be fabricated on the PC board with about 1cm (0.4") of PC board trace. Flying Capacitor Selection Warning: Polarized capacitors such as tantalum or aluminum should never be used for the flying capacitor since its voltage can reverse upon start-up of the LTC3225. Low ESR ceramic capacitors should always be used for the flying capacitor. The flying capacitor controls the strength of the charge pump. In order to achieve the rated output current, it is necessary to use at least 0.6μF of capacitance for the flying capacitor. The effective capacitance of a ceramic capacitor varies with temperature and voltage in a manner primarily determined by its formulation. For example, a capacitor made of X5R or X7R material retains most of its capacitance from –40°C to 85°C whereas a Z5U or Y5V type capacitor loses considerable capacitance over that range. X5R, Z5U and Y5V capacitors may also have a poor voltage coefficient causing them to lose 60% or more of their capacitance when the rated voltage is applied. Therefore, when comparing different capacitors, it is often more appropriate to compare the amount of achievable capacitance for a given case size rather than comparing the specified capacitance value. For example, over rated voltage and temperature conditions, a 4.7μF 10V Y5V ceramic capacitor in a 0805 case may not provide any more capacitance than a 1μF 10V X5R or X7R capacitor available in the same 0805 case. In fact, over bias and temperature range, the 1μF 10V X5R or X7R provides more capacitance than the 4.7μF 10V Y5V capacitor. The capacitor manufacturer’s data sheet should be consulted to determine what value of capacitor is needed to ensure minimum capacitance values are met over operating temperature and bias voltage. 10nH 9 VIN 0.1μF 2.2μF 8, 11 VIN LTC3225 GND 3225 F02 Figure 2. 10nH Inductor Used for Input Noise Reduction 3225f 9 LTC3225 APPLICATIONS INFORMATION The voltages on the flying capacitor pins C+ and C– have very fast rise and fall times. The high dv/dt values on these pins can cause energy to capacitively couple to adjacent printed circuit board traces. Magnetic fields can also be generated if the flying capacitors are far from the part (i.e. the loop area is large). To prevent capacitive energy transfer, a Faraday shield may be used. This is a grounded PC trace between the sensitive node and the LTC3225 pins. For a high quality AC ground it should be returned to a solid ground plane that extends all the way to the LTC3225. Table 1 contains a list of ceramic capacitor manufacturers and how to contact them. Table 1. Capacitor Manufacturers AVX www.avxcorp.com Kemet www.kemet.com Murata www.murata.com Taiyo Yuden www.t-yuden.com Vishay www.vishay.com TDK www.component.tdk.com Layout Considerations Table 2. Supercapacitor Manufacturers Due to the high switching frequency and high transient currents produced by the LTC3225, careful board layout is necessary for optimum performance. An unbroken ground plane and short connections to all the external capacitors improves performance and ensures proper regulation under all conditions. CAP-XX www.cap-xx.com NESS CAP www.nesscap.com Maxwell www.maxwell.com Bussmann www.cooperbussmann.com AVX www.avx.com TYPICAL APPLICATION 5V Supercapacitor Backup Supply D2 7 D3 9 VIN 5V C2 2.2μF 10V VO C1 1μF 10V R3 100k 5% PGOOD VIN COUT GND CX 8 1 2 4 5 C+ 10 3 LTC3225 COUT 0.80F 5.5V HS208F C3 150μF 10V C4 47μF 10V PROG PGOOD VSEL GND 7 6 10 9 R1 15k 1% C– SHDN C5 0.22μF 6.3V + 8 VIN VO VIN VO ENA SEN TYCO VO AUSTIN SUPERLYNX TRIM GND GND 1 2 3 4 VO 1.8V C7 1μF 10V C8 1μF 10V 5 6 3225 TA02 R1 23.7k 1% 11 3225f 10 LTC3225 PACKAGE DESCRIPTION DDB Package 10-Lead Plastic DFN (3mm × 2mm) (Reference LTC DWG # 05-08-1722 Rev Ø) 0.64 p0.05 (2 SIDES) 0.70 p0.05 2.55 p0.05 1.15 p0.05 PACKAGE OUTLINE 0.25 p 0.05 0.50 BSC 2.39 p0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 3.00 p0.10 (2 SIDES) R = 0.05 TYP R = 0.115 TYP 6 0.40 p 0.10 10 2.00 p0.10 (2 SIDES) PIN 1 BAR TOP MARK (SEE NOTE 6) 0.200 REF 0.75 p0.05 0.64 p 0.05 (2 SIDES) 5 0.25 p 0.05 0 – 0.05 PIN 1 R = 0.20 OR 0.25 s 45o CHAMFER 1 (DDB10) DFN 0905 REV Ø 0.50 BSC 2.39 p0.05 (2 SIDES) BOTTOM VIEW—EXPOSED PAD NOTE: 1. DRAWING CONFORMS TO VERSION (WECD-1) IN JEDEC PACKAGE OUTLINE M0-229 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 3225f Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 11 LTC3225 TYPICAL APPLICATION 12V Supercapacitor Backup Supply LT3740 HIGH EFFICIENCY DOWN CONVERTER D1 CSHD6-40C DPAK VIN 12V VIN+ + GND C1 47μF 25V DCAP VOUT LT3740 GND VOUT 1.8V 10A GND GND CHARGER 3 C2 1μF 10V VIN COUT LTC3225 + C CX C– GND 10A D2 CMSH3-20 VBIAS 3.3V C5 10μF M4 Si4410DY D3 CMSH3-20 GND C3 1μF 10V COUT VIN LTC3225 C+ CX C– 8 VM VCC LTC2915 7 SEL1 SEL2 3 6 TOL/MR RT 4 5 GND RST R7 10k R1 2k 2 R2 100k C6 0.1μF M2 IRF7424 CHARGER 2 D4 CMSH3-20 1 R6 1k 1 8 PGND OUT 2 LTC4441-1 7 SGND DRVCC 3 6 VIN IN 4 5 EN/SHDN FB M3 Si4410DY R3 332k R4 84.5k GND R5 1k M1 IRF7424 CHARGER 1 C7 10μF C4 1μF 10V COUT VIN LTC3225 + C CX C– GND 3225 TA03 RELATED PARTS PART NUMBER LTC1751-3.3/LTC1751-5 LTC1754-3.3/LTC1754-5 LTC3200 LTC3203/LTC3203B/ LTC3203B-1/LTC3203-1 LTC3204/LTC3204B-3.3/ LTC3204-5 LTC3221/LTC3221-3.3/ LTC3221-5 LTC3240-3.3/LTC3240-2.5 LT®3420/LT3420-1 LT3468/LT3468-1/ LT3468-2 LTC3484-0/LTC3484-1/ LTC3484-2 LT3485-0/LT3485-1/ LT3485-2/LT3485-3 DESCRIPTION Micropower 5V/3.3V Doubler Charge Pumps Micropower 5V/3.3V Doubler Charge Pumps Constant Frequency Doubler Charge Pump 500mA Low Noise High Efficiency Dual Mode Step-Up Charge Pumps Low Noise Regulating Charge Pumps COMMENTS IQ = 20μA, Up to 100mA Output, SOT-23 Package IQ = 13μA, Up to 50mA Output, SOT-23 Package Low Noise, 5V Output or Adjustable Micropower Regulated Charge Pump Up to 60mA Output Step-Up/Step-Down Regulated Charge Pumps 1.4A/1A Photoflash Capacitor Charger with Automatic Top-Off 1.4A/1A/0.7A, Photoflash Capacitor Charger Up to 150mA Output Charges 220μF to 320V in 3.7 Seconds from 5V, VIN: 2.2V to 16V, ISD < 1μA, 10-Lead MS Package VIN: 2.5V to 16V, Charge Time = 4.6 Seconds for the LT3468 (0V to 320V, 100μF, VIN = 3.6V), ISD < 1μA, ThinSOTTM Package VIN: 1.8V to 16V, Charge Time = 4.6 Seconds for the LT3484-0 (0V to 320V, 100μF, VIN = 3.6V), ISD < 1μA, 2mm × 3mm 6-Lead DFN Package VIN: 1.8V to 10V, Charge Time = 3.7 Seconds for the LT3485-0 (0V to 320V, 100μF, VIN = 3.6V), ISD < 1μA, 3mm × 3mm 10-Lead DFN Driver 1.4A/0.7A/1A, Photoflash Capacitor Charger 1.4A/0.7A/1A/2A Photoflash Capacitor Charger with Output Voltage Monitor and Integrated IGBT LT3750 Capacitor Charger Controller ThinSOT is a trademark of Linear Technology Corporation. VIN: 2.7V to 5.5V, 3mm × 3mm 10-Lead DFN Package Up to 150mA (LTC3204-5), Up to 50mA (LTC3204-3.3) Charges Any Size Capacitor, 10-Lead MS Package 3225f 12 Linear Technology Corporation LT 0508 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2008